Pipeline pump and water circulation system

The utility model discloses a pipeline pump and a water circulation system, which comprise a motor and a pump body, a driving shaft of the motor is connected with a pump shaft, an impeller is installed in the pump body, the pump body is provided with an installation hole used for installing and positioning the pump shaft, and the pump shaft penetrates through the installation hole and is fixed on the pump body. The end of the pump shaft is arranged at the bottom of the pump body, a sealing component is arranged at the end of the pump shaft, and the sealing component is matched with the pump shaft to form a first cavity. A hollow annular volute chamber is arranged in the pump body, the impeller is installed in the annular volute chamber, and a water return device is arranged on the annular volute chamber. The first cavity communicates with the interior of the annular volute chamber through the water return device, the temperature of the joint of the pump shaft and the pump body can be reduced during work, lubr